Wolverine
Uncanny Pompadour
A 3000KVA, 150V machine has p.u. impedance of .1 + j.6. Determine the actual impedance of the machine.
Problem 8.1
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singlespeed
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4.56 <80.5o mohm 
benbo
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Don't you square the voltage to get the base impedance?
Wouldn't that be a factor of a million?
I passed the exam but I hate pu. And I know this is about as easy as it gets.
It just seemed like a small impedance for so much current, that's why I questioned the 150 V.
Wouldn't that be a factor of a million?
I passed the exam but I hate pu. And I know this is about as easy as it gets.
It just seemed like a small impedance for so much current, that's why I questioned the 150 V.
yep would be 1,000,000:
I base = 3,000,000 VA/150 V = 20,000 A
Z base = 150 V/20,000 A (I base) = 150 V ^2/3,000,000 VA = 0.0075 ohm
I base = 3,000,000 VA/150,000 V = 20 A
Z base = 150,000 V/20 A (I base) = 150,000 V ^2/3,000,000 VA = 7500 ohm
7500/0.0075 = 1,000,000
either way it does not make much sense for a real world machine...
w/150 kV
750 + 4500 j ohms
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